Why read.csv is not detecting NA values in a datafram

I downloaded a large data set from the internet and I was inspecting the # of NA's. I'm using Rstudio btw. Something weird was happening however. I opened and closed the same project a few times accessing the data, sometimes importing the data by click from the side window, and sometimes doing it by ReadingHabits <-read.csv("ReadingHabits.csv")

For inspecting the number of missing values I do the following:

proj<-ReadingHabits sum(is.na(proj$Age)), and likewise for all of the other columns

The problem that is happening is that some of the times, it accurately picks up the 400 missing values, and sometimes it tells me 0. Does anyone have any idea why Rstudio might sometimes NOT be seeing the NA's?

I know I'm supposed to use reproducible code, but I'm not sure how to do this, so I'll include the link to where I downloaded it from

https://www.kaggle.com/vipulgote4/reading-habit-dataset

https://stackoverflow.com/questions/66147799/why-read-csv-is-not-detecting-na-values-in-a-datafram February 11, 2021 at 10:05AM